BIRDWATCHING might seem an incongruous pursuit in an urban area the size of Shanghai, but pockets of wildlife reserves still provide a valuable hunting ground for twitchers. At least for now.

One of them is the Nanhui Dongtan Wetland, on the east side of Dishui Lake in Pudong. It's only 80 kilometers from downtown Shanghai, but it's a world away in terms of environment.

In autumn and winter, it's an ideal spot for watching migratory birds passing through Shanghai or even settling in here for the winter. Here you can see ducks, swans and geese, among other birds, in a natural habitat.

But the wetland is under threat from both human and natural forces.

The Yangtze River drops volumes of sediment in the river estuary, forming sandbanks that gradually built up into solid landforms. Bound on two sides by ocean, the residents of Nanhui have long been trying to expand their land resources to accommodate farming, aquaculture, housing complexes and even factories.

Natural disasters like typhoons, storms and high tides also take their toll on the area. The locals have been busily building seawalls for years to protect their land and homes.

The reclamation of tidelands in Nanhui Dongtan has been accelerating, turning more of the area into usable land resources. That is crimping the habitat and food supply of birds.

I have visited Nanhui Dongtan twice in the past year, accompanied by He Xin, who conducts bird surveys there at least twice a month. My first visit was in late winter to see the geese and ducks. The second was last month, where the focus was on both water birds and forest birds.

On our trip on September 21, He spotted 6,907 birds of 80 species in the area.

“That number is higher than last year, which shows the birds are more concentrated in this location due to the worsening conditions of other habitats,” he explained.

Is the wetland in Nanhui Dongtan heading for the same fate as land reclamation projects nip at its heels and natural tidelands are fast disappearing?

In my two trips to the same spots in Nanhui within one year, I could see the changes. More land is being hived off for agricultural or construction projects.

Benthos, or small organisms found in bottom sediment, provide crucial food for birds. The abundance of benthos is waning. There are simply fewer and fewer mollusks, crustaceans and insects to feed on.

Nanhui Dongtan used to be abundant in benthos, attracting a large array of birds like tundra swans to the wetland area. As the biodiversity of the wetlands diminishes, the birds and other wildlife diminish, too. Reclamation on tidal flats alters salinity, tidal action and the composition of sediment, according to 2012 research published by the School of Life Sciences at East China Normal University.

This is the time of year in the Northern Hemisphere when large flocks of birds from as far away as Siberia undertake their annual migration to the warmer climes. Shanghai is located in the middle of one of the great migration routes.

The best location for viewing migratory birds is in the Nanhuizui Guanhai Park, located to the southeast of Lingang New City on the East China Sea. It's close to Dishui Lake and accessible via bus from the lake.

Educating urbanites about ecosystems

More than 200 people joined in this year's Bioblitz at the Shanghai Binjiang Forest Park near the mouth of the Huangpu River in Pudong on September 24. Nature experts and volunteers were on hand to explain the 74 plant species and dozen or so bird species in the area.

The annual event, organized by the Shanghai Wildlife Conservation Management Station, has been running for seven years. Its goal is to educate the public about nature, biodiversity and environmental protection.

The six-hour course was divided into four groups focusing on birds, plants, insects and aquatic organisms. The outing included two-and-a-half hours of field study in the morning and a nature notebook writing session to catalog observed species in the afternoon.

A team of more than 20 scientists from East China Normal University and Shanghai Normal University led the various focus groups, and 10 volunteers helped participants find plants and animals in the wild.

Bioblitz is a public biological survey that originated in the US. The first Bioblitz was held in Washington in 1996.

These events are normally held in parks or nature reserves near cities, to encourage more urban understanding of nature. Bioblitz also provides participants with the methods and tools to conduct their own nature surveys.